As a result of the ever-increasing population there has arisen a growing need for high-value nourishment. Accordingly, there is an increasing interest in the production of protein from hydrocarbons. The method of producing protein-products is the microbiological production of single cell protein (SCP for short) by cultivating SCP forming micro-organisms such as yeasts or bacteria. To this end several processes have already been put forward for the carrying out of biological fermentation processes, and various raw materials have been tried out as substrates for the production of SCP. Carbohydrate-waste products from industry have already been utilised, such as molasses, sawdust from wood-workings, and sulphite-liquor which occurs in the cellulose industry.
More recent processes use as substrates products obtained from oil. Micro-organisms have been discovered which can live on crude-oil, n-paraffins, methane, methanol and ethanol. However, the production of SCP of the quality required for foods has so far given considerable difficulty. In employing n-paraffins as substrates, bacteria are widely used which give rise to insuperable problems in the control of the process and the danger of infection in the culture-medium. There are, furthermore, difficulties in the homogeneous preservation of the four-fold mixture of n-paraffin, water, air (or oxygen) and solid. The substrate raw materials oil and n-paraffin, moreover, contain toxic materials which must be removed, by means of costly purification processes, either from the substrate itself or from the end product, the bio-mass. Complete purification and the production of a bio-mass which contains no trace of this kind of undesirable material are however impossible to achieve in practice. Thus, until now, the admissibility of such SCP products as foodstuffs has been resisted by official bodies and consumer organisations.